The present invention relates to a plug-in type contact arrangement for the coupling of electrical apparatus, such as apparatus and switch gear or their components used in high power applications and, which may have a circular, eliptical or angular cross-section as well as a rod-like shape for its first contact member, including also a second contact member having contact fingers formed thereon. In the second contact member the contact fingers are arranged according to the contour or shape of the first contact member and, wherein at their one end the contact fingers are secured in a component of the second contact member, while at their other end the contact fingers are provided with sliding contact means or roller type contact elements. Both contact members are displaceable relative to each other and in the axial direction. As a result of such displacement possibility, both contact members come into a contact relationship with each other when in an operational state.
Such plug-in type contacts are preferably employed in high power applications, where currents of more than 630 amperes are to be transmitted and where an interruption of the contacting assembly becomes necessary from time to time, such as, for checking the apparatus of the electrical gear served by the contact members. Such plug-in type contact arrangement becomes desirable also in an area where a visible separation of the circuit is necessary to indicate the operational state of the apparatus, such as, when the contact members are components within an electrical interrupter or part of a contact assembly between electrical power switches and switch gear, or for example, in an area where the electrical power switch gear should at least partially protrude from the apparatus.
Contact arrangements for a plug-in type electrical couplings of electrical apparatus, electrical gear and/or switching arrangements, which comprise a pair of axially displaceable contact members which come into a contact arrangement with each other by means of sliding or roller contacts, are known from German Patent Nos. 25 25 082 and 11 29 213.
Roller contacts enjoy an advantage over sliding contacts in that the force necessary for the relative movement of the contact members is reduced in them. Roller contacts are made up from a plurality of conducting members which are shaped in a rotational - symmetrical fashion and, which are rotatably journaled. They became known in different geometrical forms, such as in truncated cone shape (German Patent No. 11 67 946), as spherically shaped (German Patent No. 12 05 172), as spherical segment shaped (German Patent No. 10 03 323), as well as in disc shape arranged in pairs along a single axis (German Patent No. 10 40 653), and also as in the form of cylindrically shaped rollers (German Patent No. 12 16 968).
The contact force with which one of the contact members is pressed onto the other member, is brought about mostly by means of steel springs which are constructed as spiral or leaf springs, (see for example, German Patent Nos. 11 67 946 and 11 42 940). Such arrangements transmit, as far as requirements are concerned, considerable contact forces, therefore, they require a large number of roller contacts and posses undesirable radial dimensions which may unfavorably effect the spacing of the conductors and, thereby, the dimensions of the apparatus and of the switch gear.
In order to eliminate such disadvantages, plug-in tyep couplings became known, wherein the elements which are intended for carrying the electrical current are simultaneously used for producing the contact pressure (German Patent No. 11 45 254). Such elements are finger-shaped, serve as contact springs and they are manufactured from electrically good conducting material, such as, copper alloys and, are provided with rollers located in grooves at their ends facing the movable contact member, which rollers are in contacting relationship with grooves in the movable contact member. The contact springs under a bending load are capable of providing only an undefined contact force, since the bending itself is dependent to a large extent on the length of the transversely bending portions. In the event an offset develops between the axes of the movable contact member and of the fixed contact member due to manufacturing or assembly tolerances, then this will result in a situation where less than all the contact fingers will participate in bringing about the contacting. Such arrangement appears to be unsatisfactory also for the above-mentioned plug-in connection type applications for the reasons, that it can bring about a reliable contact state between the movable and fixed contact members only if there is a defined spacing between them.